Many routine treatments employed in modern clinical practice involve percutaneous insertion of needles and catheters, such as for biopsy or drug delivery. The aim of a needle insertion procedure is to place the tip of an appropriate needle safely and accurately in a lesion, organ or vessel. Examples of treatments requiring needle insertions include vaccinations, blood/fluid sampling, regional anesthesia, tissue biopsy, catheter insertion, cryogenic ablation, electrolytic ablation, brachytherapy, neurosurgery, deep brain stimulation and various minimally invasive surgeries.
There is a growing trend of performing needle insertion with offline or intra-operative image guidance. Guiding the needle based on offline images has a disadvantage, because the patient keeps breathing and the offline image then becomes historic in nature. In addition, because of gravitational force the abdomen soft tissues deform with time. The imaging scan is thus valid for several seconds only.
Even when the needle is inserted under real-time, fluoroscopic vision of the needle insertion procedure is not simple and requires proficient performance. Moreover as shown in the PCT published application WO 2007/141784 for “Controlled Steering of a Flexible Needle”, having a common co-inventor with the present application, the needle can be inserted in numerous ways even when the needle tip is required to follow the same trajectory.
In order to overcome these difficulties and improve needle placement accuracy, use is made of the model for flexible needle steering and control in soft tissue, as described in the above referenced PCT. As shown there, the manipulation required on the needle base is too complex to perform manually. Therefore the needle insertion is performed with a robot.
In a typical robotic image guided needle insertion procedure, the needle insertion will be done step-wise. The needle is not inserted in a single iteration for safety reasons. The usual procedure flow is as follows:
1. An image is taken with the needle and the target.
2. The operator analyses the image and decides whether correction to the movement is necessary.
3. The robot is then commanded to move the needle by the next step.
It can take from several seconds to several minutes to take the image and to decide how to proceed. During this time the patient continues breathing with the needle inside his/her body, such that its position is constantly changing, albeit quasi-periodically. Even when the procedure is performed without operator feedback, being based only on image data, besides the quasi-periodic breathing motion, the patient may also move his body because of pain or a cough. If the needle base is held stiffly by the insertion robot, a fixed needle could cause injury, or at least discomfort or pain to the patient.
There therefore exists a need for an automatic needle insertion system which reduces or eliminates the danger of the insertion procedure, and reduces discomfort to the subject.
The disclosures of each of the publications mentioned in this section and in other sections of the specification, are hereby incorporated by reference, each in its entirety.